1. My son has an 89 Olds 88 with both rear doors that just won't open. Previous owner said they used to open... but then one day they just wouldn't.

Have no idea where to start since I can't open them to get to the latch to oil them... can I take the panels off of them from the inside without them having to be opened?

2. Same car also is throwing a code 41 which I'll put in another topic if there isn't already one when I'm ready to tackle that one.

3. I also believe it has a blown head gasket as the coolant seems to be getting oil in it, but the oil doesn't look different. Can it only leak one way or will it always leak both ways? I've read about Blue Devil with varying degrees of recommendations.

Your thoughts on any of these 3 issues with this vehicle? I really look forward to your insights.